Increase in CD8+ Effector Memory Cells Re-Expressing CD45RA Reflects Disease Activity and Enables Early Prediction of Therapeutic Outcome in Rapidly Progressive Alopecia Areata

This study investigated the role of CD8+ effector memory cells re-expressing CD45RA (TEMRA) in rapidly progressive alopecia areata (RPAA) and their potential to predict therapeutic outcomes following intravenous corticosteroid pulse therapy (IVPT). Involving 26 RPAA patients, the study found that TEMRA cells were significantly increased in non-responders (those with < 50% hair regrowth) compared to responders, both before and after IVPT. Non-responders' TEMRA cells exhibited 3.3-fold greater cytotoxicity when exposed to trichohyalin. Histological analysis showed a higher proportion of TEMRA cells in non-responders' peribulbar regions, correlating with their frequency in peripheral blood mononuclear cells (r = 0.74). These results suggest that monitoring TEMRA cells could help evaluate disease activity and predict therapeutic outcomes in RPAA.